RESUMO

Wood residues, as well as those from poultry farming, are generally disposed of irregularly, which causes damage to the environment, and thus poses a great challenge in terms of their use, a possible alternative is the manufacture of particleboards. For this, the following mechanical properties of the panels were evaluated: static bending (elasticity - MOE and rupture - MOR), internal bond strength (IB), Janka hardness (DJ), screw withdrawal resistance (SW), thickness swelling (TS), water absorption (WA), moisture, apparent density (DA) and density profile, in addition to morphological characterization by scanning electron microscope image. With the results obtained, it was possible to observe that the amount of residue influenced the density of the panel. The panel compaction ratio showed little variation (1.22-1.32), remaining close to the value considered ideal of 1.33. The percentage of waste added to the panels also influenced the increase in WA and TS, limiting the use of the panels to environments without humidity. The addition of the eggshell in the process negatively affected the mechanical characteristics of formulated particleboards, except for Janka hardness. The application of the resin together with the wood particles and eggshells can improve the mechanical properties. Based on the findings from this study, the medium-density particleboard produced can be used for making furniture and room partitioning without structural character.

RESUMO

The Amazon rainforest and the biodiversity hotspot of the Atlantic Forest are home to fruit trees that produce functional foods, which are still underutilized. The present study aimed to select potential functional nut donor trees from two Brazilian chestnuts, by evaluating the nutritional and antioxidant composition of the nuts and the fatty acid profile of the oil. The nutritional characteristics, antioxidants, oil fatty acid profile, and X-ray densitometry of the nuts were evaluated, as well as the characterization of leaf and soil nutrients for each parent tree. The nut oil was evaluated through Brix (%), mass (g), yield (%), and the fatty acid profile. For L. pisonis, the most nutritious nuts were produced by L. pisonis tree 4 (N > P > K > Mg > Ca > Zn > Fe) and L. pisonis tree 6 (P > Ca > Mg > Mn > Zn > Cu > Fe), and for the species L. lanceolata, L. lanceolata tree 6 (N > P > Ca > Mg > Zn > Fe > Cu) and L. lanceolata tree 2 (P > K > Mg > Zn > Cu). In L. pisonis, the highest production of anthocyanins, DPPH, total phenolics, and flavonoids was obtained from the nuts of L. pisonis tree 4 as well as for L. lanceolata, from L. lanceolata tree 1, except for flavonoids. The Brix of the oil from the nuts of both species showed no difference between the trees and the fatty acid profile with a similar amount between saturated (48-65%) and unsaturated (34-57%) fatty acids. Both species have nuts rich in nutrients and antioxidant compounds and can be considered unconventional functional foods. The data collected in the present study confirm that the nuts of these species can replace other foods as a source of selenium.

RESUMO

The particleboard industry consumes large amounts of raw material, and this type of product consumption has been increasing over the last few years. The research for alternative raw materials becomes interesting, since most of the resources come from planted forests. In addition, the investigation of new raw materials must take into account environmentally correct solutions, such as the use of alternative natural fibers, use of agro-industrial residues, and resins of vegetable origin. The objective of this study was to evaluate the physical properties of panels manufactured by hot pressing using eucalyptus sawdust, chamotte, and polyurethane resin based on castor oil as raw materials. Eight formulations were designed with variations of 0, 5, 10, and 15% of chamotte, and two variations of resin with 10% and 15% of volumetric fraction. Tests of gravimetric density, X-ray densitometry, moisture content, water absorption, thickness swelling, and scanning electron microscopy were carried out. Through the results it can be noticed that the incorporation of chamotte in the manufacture of the panels increased the water absorption and the swelling in thickness, around 100% and the use of 15% of resin decreased, more than 50%, the values of these properties. X-ray densitometry analyzes showed that the addition of chamotte alters the density profile of the panel. In addition, the panels manufactured with 15% resin were classified as P7, the most demanding type on EN 312:2010 standard.

RESUMO

Free formaldehyde is a carcinogen whose emission reduction in particleboard has been studied recently to mitigate this environmental and human health problem. One alternative to reduce the emission of formaldehyde in particleboards is by using adhesives produced from natural sources. Cardanol-formaldehyde is an environmentally friendly adhesive made with cashew nut liquid, a byproduct from the cashew chain. This work aimed to produce particleboard using cardanol-formaldehyde in place of urea. In addition, different proportions of bean straw wastes were used to replace pine wood. The combination of eco-friendly adhesive and lignocellulosic waste particles could result in a product that meets market demands while being environmentally nonaggressive. Cardanol-formaldehyde promoted a higher modulus of elasticity (MOE) (1172 MPa) and modulus of rupture (MOR) (4.39 MPa) about panels glued with urea-formaldehyde, which presented a MOE of 764 MPa and MOR of 2.45 MPa. Furthermore, the cardanol-formaldehyde adhesive promoted a 93% reduction in formaldehyde emission, with a reduction from 16.76 to 1.09 mg/100 g oven-dry board for particleboards produced with cardanol-formaldehyde, indicating potential as an adhesive in the particleboard industry.

Assuntos

RESUMO

A colagem em peças de madeira por meio de adesivos é realizada desde a época dos faraós. Com o passar dos anos as tecnologias foram desenvolvidas sobretudo nos adesivos e nas diferentes espécies madeireiras existentes, adaptando-se aos diversos usos pretendidos. Neste contexto também se pode inferir sobre os métodos de análises de sua eficácia. O objetivo desse estudo foi avaliar a resistência na linha de cola mediante o uso de dois adesivos em madeira de Paulownia tomentosa (kiri japonês). As juntas coladas foram preparadas com adesivos resorcinol formaldeído e melamina ureia formaldeído. Avaliou-se a interface madeira-adesivo por meio da espessura da linha de cola principal e secundária com uso de fotomicrografias, resistência ao cisalhamento e percentagem de falha na madeira. Os adesivos apresentaram comportamento desuniforme ao longo da linha da cola. O adesivo resorcinol formaldeído penetrou de forma mais incisiva nos elementos de vasos e raios. A madeira de kiri apresentou percentual de falha superior a 92%, independente do adesivo. A eficiência na colagem com ambos adesivos testados possibilita o uso da madeira de Paulownia tomentosa no Brasil em movelaria e construção civil.

The collage on pieces of wood using adhesives has been performed since the Pharaoh era. Over the years, technologies have been developed especially for adhesives and different species of wood, adapting to the desired diverse uses. In this context we can also infer the methods of analysis and its efficiency. The aim of this study was to evaluate the resistance in the glue-line by using adhesives in Paulownia tomentosa wood (Japanese kiri). The bonded joints were prepared with resorcinol formaldehyde and melamine urea formaldehyde adhesives. The wood-adhesive interface was evaluated by means of the thickness of the main and secondary glue-lines using photomicrographs, shear strength, and percentage of wood imperfections. The adhesives presented non-uniform behavior in the glue-line. It was possible to observe that the adhesives penetrated in the wood anatomical structures (elements of vessels and rays). The resorcinol formaldehyde adhesive had higher penetration values. The kiri wood imperfection percentage was greater than 92%, independent of the adhesive. The high efficiency observed in bonding with both adhesives allows the use of wood of Paulownia tomentosa in Brazil for furniture and civil construction.

Assuntos

RESUMO

A colagem em peças de madeira por meio de adesivos é realizada desde a época dos faraós. Com o passar dos anos as tecnologias foram desenvolvidas sobretudo nos adesivos e nas diferentes espécies madeireiras existentes, adaptando-se aos diversos usos pretendidos. Neste contexto também se pode inferir sobre os métodos de análises de sua eficácia. O objetivo desse estudo foi avaliar a resistência na linha de cola mediante o uso de dois adesivos em madeira de Paulownia tomentosa (kiri japonês). As juntas coladas foram preparadas com adesivos resorcinol formaldeído e melamina ureia formaldeído. Avaliou-se a interface madeira-adesivo por meio da espessura da linha de cola principal e secundária com uso de fotomicrografias, resistência ao cisalhamento e percentagem de falha na madeira. Os adesivos apresentaram comportamento desuniforme ao longo da linha da cola. O adesivo resorcinol formaldeído penetrou de forma mais incisiva nos elementos de vasos e raios. A madeira de kiri apresentou percentual de falha superior a 92%, independente do adesivo. A eficiência na colagem com ambos adesivos testados possibilita o uso da madeira de Paulownia tomentosa no Brasil em movelaria e construção civil.(AU)

The collage on pieces of wood using adhesives has been performed since the Pharaoh era. Over the years, technologies have been developed especially for adhesives and different species of wood, adapting to the desired diverse uses. In this context we can also infer the methods of analysis and its efficiency. The aim of this study was to evaluate the resistance in the glue-line by using adhesives in Paulownia tomentosa wood (Japanese kiri). The bonded joints were prepared with resorcinol formaldehyde and melamine urea formaldehyde adhesives. The wood-adhesive interface was evaluated by means of the thickness of the main and secondary glue-lines using photomicrographs, shear strength, and percentage of wood imperfections. The adhesives presented non-uniform behavior in the glue-line. It was possible to observe that the adhesives penetrated in the wood anatomical structures (elements of vessels and rays). The resorcinol formaldehyde adhesive had higher penetration values. The kiri wood imperfection percentage was greater than 92%, independent of the adhesive. The high efficiency observed in bonding with both adhesives allows the use of wood of Paulownia tomentosa in Brazil for furniture and civil construction.(AU)

Assuntos